The broad objective of the proposed research is to synthesize peptides for conformational investigations and for use in other biophysical and biochemical research. Three types of peptides will be prepared: (1) linear oligopeptides, (2) cyclic peptides, and (3) polytripeptides of defined molecular weight. The linear peptides will be used for both enzyme:substrate investigations and as precursors for the synthesis of cyclic peptides. The cyclic peptides to be synthesized will be of several types: (a) those with nmr labels, (b) those containing fluorescent labels, and (c) some with varying cavity sizes for use in ion-binding and ion transport investigations. The polytripeptides to be synthesized will be capable of forming triple-helical structures for use in the investigation of the enzymic action of collagenase. Following the synthesis of the peptides (and their purification and chemical characterization), conformational investigations will be undertaken. In our laboratory the emphasis will be on the determination of solution conformations mainly using nmr spectroscopic methods, but other physical-chemical techniques such as ultraviolet circular dichroism and spectrofluorimetry will be used when appropriate. The application of nmr to the determination of solution conformations of cyclic peptides is now well-documented. However, one of the main purposes of this research is to prepare cyclic peptides containing 19F, 13C, and 2H "labels" which, hopefully, will allow conformational determinations with both greater precision and having the capability of solving structures of greater complexity than heretofore. The cyclic peptides to be synthesized also will be useful for the examination of many facets of the transport of cations and peptides through lipid bilayers and some natural membranes.